Lots of talk about "root bound". Even after reading Jorge's book numerous times, I have yet to see a picture of what root bound actually looks like.

This is my my first grow in 5gallon buckets. I had been using 2gallon and was able to get 2.5oz dry per plant. When I take the plants down and discard the soil, the entire lump of soil is threaded with roots and takes a bit to break up the clumped together dirt. Is this what root bound is?